1. Field of the Invention
This invention relates to cyanoethylated derivatives of aromatic amines and to an improved process for the production of such compounds. In particular, this invention relates to an improved process for cyanoethylation of aromatic amines wherein N-monocyanoethylated aromatic amines are the predominant product. Such cyanoethylated aromatic amines are of established utility as polyurethane chain extenders, and as intermediates in the production of bactericidal substances, antioxidants and dyestuffs. The cyanoethylated aromatic amines may be hydrogenated to the corresponding 3-aminopropyl primary amine derivatives which are useful as epoxy curing agents.
2. Prior Art
Although aliphatic amines can be reacted with acrylonitrile to form the corresponding cyanoethyl amine derivative in uncatalyzed reactions, aromatic amines do not react with acrylonitrile in the absence of a catalyst. Cyanoethylation is known to proceed with aromatic amines in the presence of acidic catalyst, e.g. acetic acid, cuprous chloride, cuprous acetate and mineral acids. See for example U.S. Pat. No. 2,726,945 and U.S. Pat. No. 3,231,601. All of these catalysts are homogeneous catalysts and are unsatisfactory in that they present problems in the recovery of the desired product from the crude reaction mixture.